Yes

you do need a jacket based on the weather in Płock, Poland 1 second ago

Why? Because it's colder than a polar bear's pyjamas and it's fairly windy outside!

29°F-1°C & Clear

Wind is 12 mph19 km/h from the Southeast, gusting to 24 mph38 km/h

Date	Low	High	Wind	Day	Night
February 7	27°F-3°C	36°F2°C	14 mph22 km/h from Southeast	Mostly Cloudy	Mostly Clear
February 8	25°F-4°C	36°F2°C	10 mph16 km/h from East	Mostly Clear	Clear
February 9	24°F-5°C	36°F2°C	9 mph14 km/h from East	Clear	Clear
February 10	22°F-5°C	30°F-1°C	11 mph17 km/h from East	Partly Cloudy	Mostly Clear
February 11	22°F-5°C	35°F2°C	11 mph17 km/h from East	Mostly Clear	Mostly Clear
February 12	23°F-5°C	36°F2°C	7 mph11 km/h from Southeast	Partly Cloudy	Partly Cloudy
February 13	25°F-4°C	36°F2°C	7 mph12 km/h from East	Partly Cloudy	Mostly Cloudy

Low of 25°F-4°C, High of 36°F2°C
Wind: 10 mph16 km/h
Precipitation: None